Photo: Rosa Márquez-Costa (center) accompanied by the members of the tribunal and her thesis director.

This thesis, directed by Guillermo Rodrigo, exploits the versatility of CRISPR-Cas systems and their applications in rapid and quantitative diagnostic methods. Part of the research results have been published in the journals Analytical Chemistry, Chemical Communications, ACS Synthetic Biology and Microbial Biotechnology. The thesis was defended on September 13, 2024.

CRISPR-Cas systems evolved in prokaryotes as a powerful antiviral immune response based on the selection of specific sequences by ribonucleoproteins. In this doctoral thesis, titled “Engineering of CRISPR-Cas9-based systems for diagnostics and biocomputing”, a new viral diagnostic tool has been developed based on chain displacement activated by Cas9, one of the key pieces of the prokaryotic antiviral immune system. The precision of these enzymes was the basis of a CRISPR-Cas9-based nucleic acid detection system coupled to a lateral flow assay that produces a colorimetric visible readout, suitable for point-of-care testing. Likewise, the potential of CRISPR-Cas9 has been explored to integrate multiple different signals, especially related to biocomputing and conditional control.

Rosa Márquez Costa carried out her doctoral research in the Biosystems Design group of the Institute of Integrative Systems Biology I2SysBio (CSIC-Universitat de València) under the supervision of Guillermo Rodrigo, Senior Scientist of the CSIC in the I2SysBio. He spent six months at the Nucleic Acid Chemistry and Engineering Unit, OIST (Okinawa, Japan) under the supervision of Professor Yohei Yokobayashi. During the development of her doctoral research Rosa Márquez Costa enjoyed a contract from the FPI Research Personnel Training program (PRE2019-088531) associated with a State Plan project (PGC2018-101410-B-I00). The qualifying panel was made up of Ciara O'Sullivan (Universitat Rovira i Virgili), Manish Kushwaha (INRAE, France) and Chase Beisel (Helmholtz Institute, Germany), who rated the thesis as outstanding.